LispWorks 6.1 (32-bit) for Macintosh supports Mac OS X 10.3, 10.4, 10.5 on PowerPC, and Mac OS X 10.4, 10.5, 10.6 and 10.7 on Intel.
LispWorks 6.1 (64-bit) for Macintosh supports Mac OS X 10.5 on PowerPC, and Mac OS X 10.5, 10.6 and 10.7 on Intel.
LispWorks Release Notes and Installation Guide - 23 Dec 2011